Here’s another cannon related to a specific historical incident, on display at the Washington Navy Yard. But this one dates to more of a “political” event prior to the Mexican-American War, rather than the Civil War.
This example is one of three “Stockton Guns” delivered from 1841 to 1945 to design specifications of Robert Field Stockton, a Navy officer of considerably influence. The cannons were 12-inch caliber smoothbore guns of wrought iron construction. Up to this time, guns were typically “cast” not forged or wrought, but these were products of the early industrial revolution. Weighing around 16,700 pounds each, the guns fired 224 pound shot projectiles with 45 pound charges.  The guns were designed expressly for the USS Princeton, the first warship designed from the start as a screw propelled steam vessel (previous examples had been laid down as sailing schooners and later modified). A John Ericsson design, she used a unique “pendulum” piston engine and exhibited a very fine hull line. An advanced screw design, replacing Ericsson’s type, gave the ship some additional power output. During trials and later service, the Princeton was noted as a fast vessel.  All in all, the USS Princeton, launched in 1843 was an advanced weapon system with many highly revolutionary features for its day. And of course the pet project of Commodore Stockton.
Stockton descended from a prominent New Jersey family. His grandfather was a signer of the Declaration of Independence, and his father served in the U.S. House of Representatives. Stockton saw service in the War of 1812 and later commanded a ship operating against the African slave trade. During the 1830s, Stockton spent much time managing the considerable family business affairs, and solidified political contacts. Offered the post of Secretary of the Navy, in the Tyler administration in 1841, Stockton opted to return to naval service again and pursue the construction of his advanced warship idea.
The big 12-inch gun main battery of the ship was a major design hurdle. The wrought iron process was somewhat new for large gun manufacture. The first example of the gun was ordered from Mersey Iron Works, Liverpool, England. In proofing, a crack developed, necessitating a reinforcing iron band around the breech. A second gun was produced by Ward and Company, New York. This piece differed from the British made example by using the hot blast technique and the addition of greater breech diameter (to further reinforce against cracking). The Mersey gun was named “Oregon” and the US production was named “Peacemaker.” While the Oregon was well proofed, and further proofed after reinforcement applied, the Peacemaker did not undergo extensive testing.
Of course with all that expenditure of effort, materials, and money, the Princeton just had to be shown off to the dignitaries. In late February 1844, she operated out of the Washington Navy Yard and hosted a grand demonstration on the 28th of that month, with the attendees including President Tyler, members of the cabinet, and several congressmen. Space prohibits full discussion of the event here (please refer to the excellent articlefrom Naval History magazine from 2005 by Ann Blackman), but around mid-afternoon, during one last demonstration, the “Peacemaker” burst, killing the Secretaries of State and Navy, several others, and injuring a large portion of those visiting the ship. The President escaped injury by quirk of fate and happenstance. 
Repercussions from the explosion were both political and technical. Of course, with two members of his cabinet dead, President Tyler had a shakeup of his staff, with John C. Calhoun stepping in as the Secretary of State. In some regards, the shuffle sharpened the President’s desire to annex Texas, and placed the United States on courses which lead to war with Mexico. Stockton appears to have emerged looking like a well adjusted rose from the incident. He would deliver the proposal for Texas Annexation in 1845. And later he played a key role securing California during the Mexican-American War.
Technically speaking, the bursting of this wrought iron gun re-affirmed the use of cast iron or bronze with gun construction. One additional “Stockton” gun was delivered, but that was the last production wrought iron gun for a decade. However the incident prompted much research within the Army and Navy circles with regard to iron gun manufacture. The end result of this flurry of research were a series of advances which Civil War readers are familiar with by names such as “Rodman” and “Dahlgren.” However, the wrought iron production process in particular was taken on and perfected by Samuel Reeves of the Pheonix Iron Works in later years. Reeves tackled specific problems regarding the joins created in the forge welding processes. The best examples of his work of course, would be the 3-inch Ordnance Rifle, considered the best field rifle of the Civil War by many.
Two Stockton Guns exist today. The “Oregon” is on display at Annapolis, Maryland. A replacement for the “Peacemaker” was cast in 1845 by Mersey Iron Works, and that example is at the Washington Navy Yard today.
 Spencer Tucker, Arming the Fleet: U.S. Naval Ordnance in the Muzzle-Loading Era (Annapolis, Maryland: Naval Institute Press, 1989), p. 155.
Donald L. Canney, The Old Steam Navy, Volume One: Frigates, Sloops, and Gunboats, 1815-1885 (Annapolis, Maryland: Naval Institute Press, 1990), pp. 22-24.
 For more information about the life and career of Robert Stockton, see A Sketch of the Life of Com. Robert F. Stockton, by Samuel John Bayard and Robert Field Stockton, 1856.
 Tucker, p. 155.
James C. Hazlett, Edwin Olmstead, and M. Hume Parks, Field Artillery of the Civil War Revised Edition (Chicago: University of Illinois Press, 2004), pp. 120-121.